How to do antialiasing on a rotated UIView (NOT UIImageView)

Question

My issue is basically the the same as this one. I have a UIView and when I rotate it usding CGAffineTransformMakeRotation, the edges are not being antialiased.

I tried both adding the view as a subview in a bigger UIView and using a transparent border on the view but none of these worked.

The OP of the aforementioned post solved this by making an image with transparent borders in photoshop and using a UIImageView instead but I cannot do the same because the size of the UIView is determined on runtime.

Does anyone know any solutions to this problem?

Note that this is not a duplicate of this post because I am interested in using a UIView and NOT a UIImageView.

score 20 · Accepted Answer · answered Feb 09 '12 at 09:39

20

Try setting UIViewEdgeAntialiasing=YES in your App-info.plist

answered Feb 09 '12 at 09:39

trackmate

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Do you know if this raise the CPU usage for your app ? – Kevin Hirsch Aug 11 '14 at 09:27

score 0 · Answer 2 · answered Oct 25 '11 at 15:50

I solved this by creating a 3x3 px image in photoshop. The center pixel of the image has the color I wanted my background to have and the rest of the pixels are transparent. Then I was able to use an instance of UIImageView and to define the frame size at runtime by using the -stretchableImageWithLeftCapWidth:topCapHeight: method.

This solution, of course still does not work for UIViews but that way you can circumvent the "variable size" issue and use a UIImageView instead.

How to do antialiasing on a rotated UIView (NOT UIImageView)

2 Answers2